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##Windows PowerShell, 142 146 147 152 156 169

{$s='' -join([char[]]"$args "|%{if(90-ge$_){')'*(($x=$s.indexOf("$_".ToLower())+1)+$s.Length*!$x) $s=$s.substring($x)}else{"($_" $s="$_$s"}})} 

Some things to note: This is just a script block. It can be assigned to a variable or given a function name, if necessary. You can also run it by putting . or & in front of it and the arguments at the end. Uses a final space to terminate unclosed tags.

Passes all tests. Test script:

$tests = ("aAaAbB","(a)(a)(b)"),("abBcdDCA","(a(b)(c(d)))"),("bisSsIB","(b(i(s)(s)))"),("aAabc","(a)(a(b(c)))"),("abcdDA","(a(b(c(d))))"),("abcAaA", "(a(b(c)))(a)"),("acAC","(a(c))") "function f " + ((gc ./tags.ps1)-join"`n") | iex $tests | %{ $result = f $_[0] ("FAIL: $($_[0]):$($_[1]) - $result", 'PASS')[$result -ceq $_[1]] } 

Windows PowerShell, 142 146 147 152 156 169

{$s='' -join([char[]]"$args "|%{if(90-ge$_){')'*(($x=$s.indexOf("$_".ToLower())+1)+$s.Length*!$x) $s=$s.substring($x)}else{"($_" $s="$_$s"}})} 

Some things to note: This is just a script block. It can be assigned to a variable or given a function name, if necessary. You can also run it by putting . or & in front of it and the arguments at the end. Uses a final space to terminate unclosed tags.

Passes all tests. Test script:

$tests = ("aAaAbB","(a)(a)(b)"),("abBcdDCA","(a(b)(c(d)))"),("bisSsIB","(b(i(s)(s)))"),("aAabc","(a)(a(b(c)))"),("abcdDA","(a(b(c(d))))"),("abcAaA", "(a(b(c)))(a)"),("acAC","(a(c))") "function f " + ((gc ./tags.ps1)-join"`n") | iex $tests | %{ $result = f $_[0] ("FAIL: $($_[0]):$($_[1]) - $result", 'PASS')[$result -ceq $_[1]] } 

##Windows PowerShell, 146 147 152 156 169

{$s='' -join([char[]]"$args "|%{if(32..90-eq$_){')'*(($x=$s.indexOf("$_".ToLower())+1)+$s.Length*!$x) $s=$s.substring($x)}else{"($_" $s="$_$s"}})} 

Passes all tests. Test script:

$tests = ("aAaAbB","(a)(a)(b)"),("abBcdDCA","(a(b)(c(d)))"),("bisSsIB","(b(i(s)(s)))"),("aAabc","(a)(a(b(c)))"),("abcdDA","(a(b(c(d))))"),("abcAaA", "(a(b(c)))(a)"),("acAC","(a(c))") "function f " + ((gc ./tags.ps1)-join"`n") | iex $tests | %{ $result = f $_[0] ("FAIL: $($_[0]):$($_[1]) - $result", 'PASS')[$result -ceq $_[1]] } 

##Windows PowerShell, 142 146 147 152 156 169

{$s='' -join([char[]]"$args "|%{if(90-ge$_){')'*(($x=$s.indexOf("$_".ToLower())+1)+$s.Length*!$x) $s=$s.substring($x)}else{"($_" $s="$_$s"}})} 

Some things to note: This is just a script block. It can be assigned to a variable or given a function name, if necessary. You can also run it by putting . or & in front of it and the arguments at the end. Uses a final space to terminate unclosed tags.

Passes all tests. Test script:

$tests = ("aAaAbB","(a)(a)(b)"),("abBcdDCA","(a(b)(c(d)))"),("bisSsIB","(b(i(s)(s)))"),("aAabc","(a)(a(b(c)))"),("abcdDA","(a(b(c(d))))"),("abcAaA", "(a(b(c)))(a)"),("acAC","(a(c))") "function f " + ((gc ./tags.ps1)-join"`n") | iex $tests | %{ $result = f $_[0] ("FAIL: $($_[0]):$($_[1]) - $result", 'PASS')[$result -ceq $_[1]] } 

##Windows PowerShell, 147 152 156 169

{$s='' -join([char[]]"$args "|%{if(97..122-eq$_){"($_" $s="$_$s"}else{')'*(($x=$s.indexOf("$_".ToLower())+1)+$s.Length*!$x) $s=$s.substring($x)}})} 

Passes all tests. Test script:

$tests = ("aAaAbB","(a)(a)(b)"),("abBcdDCA","(a(b)(c(d)))"),("bisSsIB","(b(i(s)(s)))"),("aAabc","(a)(a(b(c)))"),("abcdDA","(a(b(c(d))))"),("abcAaA", "(a(b(c)))(a)"),("acAC","(a(c))") "function f " + ((gc ./tags.ps1)-join"`n") | iex $tests | %{ $result = f $_[0] ("FAIL: $($_[0]):$($_[1]) - $result", 'PASS')[$result -ceq $_[1]] } 

##Windows PowerShell, 146 147 152 156 169

{$s='' -join([char[]]"$args "|%{if(32..90-eq$_){')'*(($x=$s.indexOf("$_".ToLower())+1)+$s.Length*!$x) $s=$s.substring($x)}else{"($_" $s="$_$s"}})} 

Passes all tests. Test script:

$tests = ("aAaAbB","(a)(a)(b)"),("abBcdDCA","(a(b)(c(d)))"),("bisSsIB","(b(i(s)(s)))"),("aAabc","(a)(a(b(c)))"),("abcdDA","(a(b(c(d))))"),("abcAaA", "(a(b(c)))(a)"),("acAC","(a(c))") "function f " + ((gc ./tags.ps1)-join"`n") | iex $tests | %{ $result = f $_[0] ("FAIL: $($_[0]):$($_[1]) - $result", 'PASS')[$result -ceq $_[1]] }